CN110484816A

CN110484816A - One kind is with silicon for high tough automobile steel of aluminium lightweight and preparation method thereof

Info

Publication number: CN110484816A
Application number: CN201910819428.1A
Authority: CN
Inventors: 宋成浩; 孙振忠; 王皓亮; 马浩鹏
Original assignee: Dongguan University of Technology
Current assignee: Dongguan University of Technology
Priority date: 2019-08-31
Filing date: 2019-08-31
Publication date: 2019-11-22

Abstract

The present invention relates to one kind with silicon for the high tough automobile steel of aluminium lightweight, alloying component weight percent are as follows: C:0.1-0.4 wt.%, Si:3.5-5.5 wt.%, Mn:4.0-6.0 wt.%, Ni:0.5-1.0 wt.%, Ti:0.01-0.1 wt.%, surplus Fe；The invention further relates to a kind of with silicon for the preparation method of the high tough automobile steel of aluminium lightweight, including weighing alloying component, smelting, casting and hot-rolled process, the object of the present invention is to provide one kind with silicon for high tough automobile steel of aluminium lightweight and preparation method thereof, the material has excellent mechanical property, production cost is low, simple process, compensates for a series of problems brought by aluminium lightweight well, there is huge application prospect.

Description

One kind is with silicon for high tough automobile steel of aluminium lightweight and preparation method thereof

Technical field

The invention belongs to metal material processing technical field, being related to a kind of microscopic structure is nanostructure, is utilized with silicon generation The alloy system of aluminium prepares the high tough automobile steel of this lightweight.

Background technique

Steel material is widely used in the industries such as national defense industry and building, machinery, shipbuilding, automobile, household electrical appliances, is society and warp Help the material base developed；The production of steel material is faced with the immense pressure of the energy, resource and environment under existing situation；This Outside, with modern industry development in science and technology and national economy transition and upgrade, build high stratification, Longspan Bridge, light energy-saving automobile, Advanced railway transportation equipment, large-scale offshore equipment, high-new ship, aerospace equipment, large-scale mine mechanical equipment etc. are rapidly sent out All to indexs such as the intensity of steel material, plasticity, toughness, more stringent requirements are proposed for exhibition, in the great foundation engineering of country further Emphasize energy-saving and emission-reduction and the lightweight of traffic equipment, accelerate the transformation and upgrade of manufacturing industry green, promote steel, petrochemical industry, engineering machinery, The industries such as light industry, weaving are to the high-end development of value chain；" new material industry development guide " specifies the development of advanced steel product Direction, wherein energy conservation to be determined as to the new material of focus on the application field urgent need, high-strength vehicle steel with new-energy automobile material Research and development with application for realization energy-saving and emission-reduction and the lightweight of traffic equipment be of great significance, be dedicated to developing novel, high Tough, light-weighted steel material advantageously reduces the consumption to the energy and resource, promotes the sustainable development of socio-economy.

High tough automobile steel has been developed to the third generation at present, and typical product such as Q&P steel, low density steel, surpasses medium managese steel Grade bainitic steel etc.；The development of future automobile steel is guiding to be turned to high tough and light weight, therefore current low density steel is in The research that manganese steel combines is a lot of, but also has many problems, and several typical domestic patents of invention are set forth below and are described, And the characteristics of illustrating the invention patent and advantage；Chinese invention patent CN201810362095.X describes a kind of strength and ductility product and is greater than The automobile high strength steel and preparation method of 45GPa%, the aluminium of carbon, middle manganese and certain content is as major alloy system in System plays the role of reducing density, and by hot rolling, cold rolling and annealing, making tensile strength is more than 1000MPa, and strength and ductility product is greater than 45GPa%, but carbon and higher alloy system in being used in the invention, for the structural member for undertaking welding and forming It is unsuitable, and the Al of high level can seriously reduce the rigidity of material, this is also not for automobile load-bearing part Suitably, it is therefore desirable to meet the high tough automobile steel of the current and following lightweight from the redesign of alloy system design angle； Chinese invention patent CN201810507557.2 describes a kind of 1200MPa grade high-strength high-ductility low-density steel plate and its manufacture Method uses high-carbon, Gao Meng, high-aluminium alloy system, and tensile strength is more than 1200MPa, and elongation percentage is greater than 30%, although this is specially The steel grade performance that benefit is introduced is very excellent, but is also the problem of CN201810362095.X patent above is embodied occur, and one Be that weldability and formability are worse, second is that plus excessively high aluminium rigidity reduce more, and continuous casting process is extremely difficult in actual production, In addition, this alloy content is excessively high, cost is significantly improved, and is not suitable for the development of current and future automobile steel, and Chinese invention is special Sharp CN201310733931.8 describes a kind of preparation of the strong automobile steel of 1400MPa grades of low yield strength ratio high-elongation cold rolling superelevation Method obtains tensile strength greater than 1400MPa using low-carbon and low-alloy system, and with simple preparation process, and elongation percentage is greater than Steel plate equal to 8%, but its design microscopic structure based on conventional mar battened construction, tensile strength up to 1500MPa Left and right, is not able to satisfy the requirement of alternative thermoforming steel, and the following safer anti-collision structure part needs higher intensity to prop up Support, therefore, based on the above-mentioned correlation analysis about lightweight and martensite strengthening, embodies current design and research meets future The deficiency of automobile steel development, this is also that the present invention to be overcome.

Summary of the invention

The object of the present invention is to provide one kind with silicon for high tough automobile steel of aluminium lightweight and preparation method thereof, the material With excellent mechanical property, production cost is low, simple process, compensates for a series of brought by aluminium lightweight ask well Topic, there is huge application prospect.

In order to achieve the goal above, the technical solution adopted by the present invention are as follows: one kind is with silicon for the high tough automobile of aluminium lightweight With steel, alloying component weight percent are as follows: C:0.1-0.4 wt.%, Si:3.5-5.5 wt.%, Mn:4.0-6.0 wt.%, Ni: 0.5-1.0 wt.%, Ti:0.01-0.1 wt.%, surplus Fe.

Another technical solution of the invention it is a kind of with silicon for the preparation method of the high tough automobile steel of aluminium lightweight, including Following steps；

1) alloying component, is weighed, weighs corresponding C, Si, Mn, Ni, Ti and Fe according to alloying component weight percent；

2) it, smelts, cast, the slab that alloying component weighed in step 1) is subjected to vacuum metling, is cast as 40-80mm thickness；

3) then, hot rolling is carried out by the slab of 40-80mm thickness in 1200-1250 DEG C of heat preservation 2.0-2.5h at 1100-1150 DEG C Hot rolling, total reduction 90-96% obtain the hot rolled plate with a thickness of 2.4-4.0mm, and silicon as of the invention is high for aluminium lightweight Tough automobile steel.

The invention has the benefit that

1, the Ni of the Si and 0.5-1.0wt.% of 3.5-5.5wt.% are added in alloy system, the Si of this content range can be replaced The light weight effect that the Al of 2wt.% is played, and avoid that rigidity brought by Al lightweight is low and carbide is complicated, changeable etc. lacks It falls into, and solid solution strengthening effect caused by Si is 350-500MPa, and the intensity of steel can be significantly increased；Too high amount Si is added Afterwards, the brittleness of steel is reinforced, and the ductile-brittle transition temperature of steel can be improved in Ni, is added 0.5-1.0 wt.%'s according to Si content range Ni is cracked when can effectively avoid hot rolling, so realizes the light weight effect that silicon is played for aluminium, and avoid Al light weight The defects of rigidity brought by changing is low and carbide is complicated, changeable, while also ensuring rigid toughness.

2, the Mn of the C and 4.0-6.0wt.% of 0.1-0.4 wt.% are added in alloy system, hot rolled plate can be made to generate certain body Product content, stable retained austenite, C, Mn content ratio of this range can be such that retained austenite generates during stretching gradually Variant TRIP effect effectively improves the strong plasticity of steel.

3, the Ti of 0.01 ~ 0.1wt.%, and N content in strict control smelting process steel is added, so that it is less than 40ppm, makes steel Middle formation nano-scale and distribution disperse, uniform TiC precipitated phase, fining austenite grains, while it is strong to further enhance matrix Degree, improves the obdurability of steel.

The present invention is based on the design of scientific and rational alloy system, and by smelting and hot rolling technology, preparation has nanometer The ultra-high strength and toughness lightweight automobile steel of battened construction；It is of the invention it is innovative embody it is as follows: 1) pass through thermodynamics, dynamics and Physical metallurgy principle carries out realizing that light-weighted alloy system designs for aluminium with silicon, and uses low-carbon and low-alloy system；2) with On the basis of silicon is for aluminium, by theoretical calculation and experimental verification, the Ni of certain content is added, can offset brought after introducing Si Brittleness；1) and 2) 3) Ti of certain content is added on the basis of, and cooperates specific hot rolling technology, can be obtained containing nanometer Lath structure, and tensile strength is more than the high tough automobile steel of lightweight of 2000 MPa；With silicon for aluminium prepared by the present invention Nanometer martensite lath width is 62-103nm, hot rolling in the high tough automobile hot rolled plate of lightweight with nanometer battened construction The mechanical property of plate are as follows: tensile strength 1750-2258MPa, elongation after fracture 5.1-17.0%.

Detailed description of the invention

Fig. 1 is nanometer martensite lath images of transmissive electron microscope in the embodiment of the present invention 1；

Fig. 2 is nanometer martensite lath images of transmissive electron microscope in the embodiment of the present invention 2；

Fig. 3 is nanometer martensite lath images of transmissive electron microscope in the embodiment of the present invention 3；

Fig. 4 is nanometer martensite lath images of transmissive electron microscope in the embodiment of the present invention 4.

Specific embodiment

In order to make those skilled in the art more fully understand technical solution of the present invention, the present invention is retouched in detail below State, the description of this part be only it is exemplary and explanatory, should not have any restriction effect to protection scope of the present invention.

Embodiment 1:

It is a kind of with silicon for the preparation method of the high tough automobile steel of aluminium lightweight, include the following steps；

1) alloying component, is weighed, Si, 4.0wt.% of C, 3.5wt.% of 0.1wt.% are weighed according to alloying component weight percent Mn, 0.5wt.% Ni, 0.01wt.% Ti, surplus Fe；

2) it, smelts, cast, the slab that alloying component weighed in step 1) is subjected to vacuum metling, is cast as 40mm thickness；

3), hot rolling, by the slab of 40mm thickness in 1200 DEG C of heat preservation 2.5h, then in 1100 DEG C of progress hot rollings, finishing temperature 950 DEG C, hot rolling to 3mm, total reduction 92.5% is air-cooled to room temperature and obtains silicon of the invention for the high tough automobile of aluminium lightweight Steel；It is organized based on nanometer martensite lath and high dislocation density, statistical analysis, the average width of nanometer martensite lath Degree is 103nm, sees Fig. 1, mechanical property is as shown in table 1.

1 hot rolled plate mechanical property of table

Embodiment 2:

1) alloying component, is weighed, Si, 6.0wt.% of C, 5.5wt.% of 0.4wt.% are weighed according to alloying component weight percent Mn, 1.0wt.% Ni, 0.1wt.% Ti, surplus Fe；

2) it, smelts, cast, the slab that alloying component weighed in step 1) is subjected to vacuum metling, is cast as 80mm thickness；

3), hot rolling, by the slab of 80mm thickness in 1250 DEG C of heat preservation 2.5h, then in 1150 DEG C of progress hot rollings, finishing temperature 950 DEG C, hot rolling to 4mm, total reduction 95% is air-cooled to room temperature and obtains silicon of the invention for the high tough automobile steel of aluminium lightweight； It is organized based on nanometer martensite lath and high dislocation density, statistical analysis, nanometer martensite lath mean breadth are 62nm, is shown in Fig. 2, and mechanical property is as shown in table 2.

2 hot rolled plate mechanical property of table

Embodiment 3:

1) alloying component, is weighed, Si, 5.2wt.% of C, 4.8wt.% of 0.2wt.% are weighed according to alloying component weight percent Mn, 0.6wt.% Ni, 0.07wt.% Ti, surplus Fe；

2) it, smelts, cast, the slab that alloying component weighed in step 1) is subjected to vacuum metling, is cast as 60mm thickness；

3), hot rolling, by the slab of 60mm thickness in 1230 DEG C of heat preservation 2.4h, then in 1130 DEG C of progress hot rollings, finishing temperature 950 DEG C, hot rolling to 2.4mm, total reduction 96% is air-cooled to room temperature and obtains silicon of the invention for the high tough automobile of aluminium lightweight Steel；It is organized based on nanometer martensite lath and high dislocation density, statistical analysis, the average width of nanometer martensite lath Degree is 70nm, sees Fig. 3, mechanical property is as shown in table 3.

3 hot rolled plate mechanical property of table

Embodiment 4:

1) alloying component, is weighed, Si, 6.0wt.% of C, 5.5wt.% of 0.3wt.% are weighed according to alloying component weight percent Mn, 1.0wt.% Ni, 0.1wt.% Ti, surplus Fe；

3), hot rolling, by the slab of 40mm thickness in 1210 DEG C of heat preservation 2.1h, then in 1110 DEG C of progress hot rollings, finishing temperature 950 DEG C, hot rolling to 4mm, total reduction 90% is air-cooled to room temperature and obtains silicon of the invention for the high tough automobile steel of aluminium lightweight； It is organized based on nanometer martensite lath and high dislocation density, statistical analysis, nanometer martensite lath mean breadth are 65nm, is shown in Fig. 4, and mechanical property is as shown in table 4.

4 hot rolled plate mechanical property of table

In conclusion in the present invention hot rolled plate tensile strength range be 1750 ~ 2258MPa, elongation after fracture be 5.1 ~ 17.0%, there is good strong plasticity, be mainly due to alloy system design and nanometer martensite of the present invention with silicon for aluminium Battened construction design.

Several common lightweight steel are set forth below, to prove significant advantage of the invention.

Comparative example 1:

Typical third generation automobile steel QP steel, composition range: C 0.15-0.35 wt.%, Si 1.0-2.0 wt.%, Mn 1.4-2.5 wt.%, remaining is Fe；After casting, hot rolling, cold rolling, QP heat treatment, mechanical property are as follows: tensile strength 900- 1300 MPa, elongation after fracture 15-30%；Comprehensive mechanical property is fine, but low strength, is unable to reach superhigh intensity level, And heat treatment process is complicated, high production cost.

Comparative example 2

Mn steel in typical third generation automobile steel, composition range: C 0.15-0.40wt.%, Si0.5-2.0 wt.%, Mn3.5- 9.0 wt.%, remaining is Fe ' after casting, hot rolling, cold rolling, solution treatment, mechanical property are as follows: tensile strength 900-1400 MPa, elongation after fracture 20-40%；Comprehensive mechanical property is very excellent, but tensile strength is unable to reach superhigh intensity rank；In and There is no the density for fundamentally playing the role of reducing steel for the alloy system of manganese steel and QP steel.

Comparative example 3

Low density steel in typical third generation high-strength steel, composition range: C 0.2-0.8wt.%, Si0.2-2.0 wt.%, Mn3.5-9.0 wt.%, Al 1.5-7.0 wt.%, remaining is Fe, after casting, hot rolling, cold rolling, solution treatment, mechanical property It can are as follows: tensile strength 700-1200 MPa, elongation after fracture 25-50%；Comprehensive mechanical property is fine, but low strength, can not Reach superhigh intensity level, and rigidity reduction after Al is added, the easy water blocking mouthh of continuous casting is not easy to realize industrial production.

Therefore in conclusion the present invention overcomes the defect of above-mentioned comparison case, there is significant advantage.

It should be noted last that above embodiments are only technical solutions to the present invention rather than limit；Although referring to reality Applying example, invention is explained in detail, it will be apparent to an ordinarily skilled person in the art that technical solution of the present invention It is modified or replaced equivalently, without departure from the spirit and scope of technical solution of the present invention, should all cover of the invention In scope of the claims.

Claims

1. one kind is with silicon for the high tough automobile steel of aluminium lightweight, which is characterized in that alloying component weight percent are as follows: C:0.1- 0.4 wt.%, Si:3.5-5.5 wt.%, Mn:4.0-6.0 wt.%, Ni:0.5-1.0 wt.%, Ti:0.01-0.1 wt.%, it is remaining Amount is Fe.

2. it is as described in claim 1 it is a kind of with silicon for the preparation method of the high tough automobile steel of aluminium lightweight, which is characterized in that Include the following steps；